Spastic paralysis suggests involvement of b) upper motor neurons. This condition is characterized by increased muscle tone and exaggerated reflexes, which occur due to damage to the upper motor neurons that originate in the brain and connect to the spinal cord.
When the upper motor neurons are injured, the signals that inhibit the muscle contractions are disrupted, leading to the spastic state. In contrast, damage to lower motor neurons would typically result in flaccid paralysis, where there is decreased muscle tone and reduced reflexes.
Therefore, the correct answer is that spastic paralysis is primarily associated with the dysfunction of upper motor neurons.